SoFi Number

A SoFi (Social Fiscal) number is a 9 digit number used in the Netherlands, which is protected by a special numerical check.
Each digit is multiplied by a factor ranging from 9 to 1. The calculation results are then summed together (the last result is substracted, rather than added). Finally, to be a valid SoFi number, the sum must be divisible by 11.

Example (SoFi number: 8765.45.678):

8 7 6 5 . 4 5 . 6 7 8
* * * * * * * * *
9 8 7 6 5 4 3 2 1
= = = = = = = = =
72 + 56 + 42 + 30 + 20 + 20 + 18 + 14 - 8 = 264 = N*11

Example (SoFi number: 3737.37.373):

3 7 3 7 . 3 7 . 3 7 3
* * * * * * * * *
987654321
= = = = = = = = =
27 + 56 + 21 + 42 + 15 + 28 + 9 + 14 - 3 = 209 = N*11


1998-02-26